Table 2

Temperature t, C	Temperature Т, К	1/Т, К–1	Semiconductor resistance R, Ω		Forbidden band width J
20
30
40
50
60
70
80
90
100

3.3. Draw the graph semiconductor resistance logarithm against inverse temperature using data from table 2.

3.4. Determine of graph inclination to the x-axis:

= ___________.

Enter the results of determination into table 2. Obtained value corresponds to the forbidden band width.

Conclusions

The data of laboratory work fulfillment

Pass mark Signature

Mark of laboratory work defence Signature

q uestions to be admitted for doing laboratory work and its defending

1. What is metal conductivity?

2. What does metal conductivity depend on?

3. Write down the law for temperature dependence of metal resistance.

4. Write down the law for temperature dependence of semiconductor resistance.

5. Give theoretical explanation for temperature dependence of metal resistance.

6. Give theoretical explanation for temperature dependence of semiconductor resistance.

7. Why does metal resistance grow while temperature increases?

8. Why does semiconductor resistance diminish while temperature increases?

9. How is temperature coefficient of metal resistance determined?

10. What substances are named semiconductors?

11. What substances are called intrinsic (pure) semiconductors?

12. What substances are called extrinsic (impurity) semiconductors?

13. How is forbidden bands width of a semiconductor determined?

LABORATORY WORK

STUDY OF RADIOACTIVITY PHENOMENON. DETERMINATION OF COEFFICIENT OF γ-RAYS ABSORPTION BY SUBSTANCE

The purpose of the work: to study radioactivity phenomenon; to determine coefficient of γ-rays absorption by lead

Devices and accessories: 1. radiometer 2. gas-filled counter 3. radioactive specimen 4. set of lead plates

Task 1. Take data for laboratory work fulfilment

1. Take data for calculations according to the variant, given by a teacher.

Enter the results into table 1.

Table 1

Exp. No	Counter background. Pulse amount n0 per 100 s	Counter background. Pulse amount n0 per 1 min	Counter background. Average value of pulse amount n0 per 1 min	Lead plate width, x, сm	Pulse amount n (phosphor) per 100 s	Pulse amount n (phosphor) per 1 min	Average value of pulse amount nave per 1 min	Average value of pulse amount Nave per 1 min with background
1
2
3
1
2
3
1
2
3
1
2
3

2. Draw graph of the dependence using data from table 2.

Table 2

	Lead plate width, x, cm		Linear absorption factor, 	Lead density, , kg/m3	Mass absorption factor, 
				11,3 · 103

3. Determine angle tangent of graph inclination to the x-axis. Enter the results into table 3.

= ___________ .

4. Determine mass absorption factor of lead according to the formula:

.

Conclusions

The data of laboratory work fulfilment

Pass mark Signature

Mark of laboratory work defence Signature

q uestions to be admitted for doing laboratory work and its defending

1. What does radioactivity phenomenon consist in?

2. What are the types of radioactivity?

3. Write down and formulate the radioactive decay law.

4. Give the determination of radioactive decay constant.

5. What is radioactive isotope half-life?

6. What types of radioactive decay do you know? What does displacement rule consist in?

7. Give the definition of α-, β- and γ-decays.

8. Explain the origin of α-, β-decays.

9. What is penetrability of γ-rays in a substance?

10. Write down the law of γ-rays absorption by a substance.

Q UESTIONS FOR CURRENT TEST PAPERS AND MODULE CONTROL

(theoretical information)

1. Thermal radiation. Energy characteristics of thermal radiation. Perfectly black body model.

2. Kirhhoff’s law for thermal radiation.

3. Stefan-Boltzmann law.

4. Wien’s displacement Law.

5. «Violet catastrophe».

6. Planck’s quantum hypothesis, Planck’s formula.

7. Deduce Stefan-Boltzmann law and Wien’s displacement law using Planck’s formula.

8. Thermal radiation laws application.

9. Photoelectric effect. Photoelectric effect laws.

10. Photoelectric effect threshold and stopping potential.

11. Einstein’s theory of photoelectric effect.

12. Photon and its characteristics.

13. practical application of photoeffect.

14. Light pressure.

15. Compton’s effect.

16. De Broglie’s hypothesis.

17. Experiments of Davisson and Germer.

18. Heisenberg’s principle of uncertainity.

19. Wave function and Schrodinger’s equation.

20. Free particle motion.

21. Electron in potential box.

22. Electron in potential well.

23. Tunnel effect.

24. Linear harmonic oscillator.

25. Rutherford Model of atom and radiation problem.

26. Bohr’s postulates.

27. Balmer’s series formula.

28. Franck and Hertz experiments.

29. Physical quantities quantization: energy, momentum, angular momentum, space quantization.

30. Quantum numbers. Pauli’s principle. Electrons distribution by their states.

31. Spectrums of multielectronic atoms. Zeeman’s Effect. Characteristic X-ray spectra.

32. Spontaneous and forced radiation. Quantum generators.

33. Composition and properties of nucleons.

34. Atomic nucleus properties. Energy levels.

35. Atomic nucleus quantum descriptions.

36. Fundamental interaction in nature.

37. Nuclear forces properties. Virtual pion.

38. Nucleus binding energy. Specific binding energy.

39. Nucleus models. Characteristics.

40. Radioactive decay. Law of radioactive transformation (deducing).

41. Half-life, activity.

42. Alpha decay. Peculiarities, characteristics.

43. Beta-decay. Peculiarities, characteristics.

44. Gamma-decay. Peculiarities, characteristics.

45. Nuclear reactions. Types and features of nuclear reactions.

46. Nuclear reaction effective cross section.

47. Methods of nuclear reactions recording. Nuclear reaction energy.

48. Elementary particles. Quantum characteristics and mutual transformations of elementary particles.

49. Conservation laws.

50. Elementary particles classification.

51. Quarks: classification and characteristics.

52. Quarks interaction